In electrical equipment on-board aircraft, low weight and compactness are critical parameters in the design thereof. In order to more easily repair and replace individual electronic components, most of them are mounted on easily removable circuit board modules. The circuit board modules are rack mounted in cabinets and, typically, are automatically plugged into mother boards upon insertion. The weight and size limitations require that they be closely packed in the cabinets and, since a great many of these components generate heat when in operation, both air and liquid cooling systems have been used. One such method is to clamp the circuit board modules to the mounting guide rails in the cabinet and use the guide rails to transfer and distribute the heat to a solid metal guide rail support plate. Cooling fluid is pumped over the back side of the plate absorbing the heat, and thus, transferring the heat out of the cabinet. However, for this system to be effective, the rail support plates must be relatively large in order to conduct the heat from the guide rails and effectively couple it to the circulating coolant fluid. This, of course, adds weight to the system.
In U.S. Pat. No. 4,315,300 "Cooling Arrangement for Plug-In Module Assembly" by James K. Parmerlee et al. the circuit boards are slideably mounted in grooved end plates which act as heat sinks. The end plates have straight-through coolant passages in the outer ends thereof for extraction of heat. Additionally, the circuit boards are spaced sufficiently apart to allow air to be fan driven down between the boards to provide additional cooling. However, this system provides no means for thermal clamping of the circuit boards to the walls of the grooves and the end plates still must be large in order to conduct heat from the groove walls. Additionally, the requirement for "air cooling" dictates that the circuit board modules be spaced apart, decreasing the density thereof.
U.S. Pat. No. 3,917,370 "Interconnect Device for Use in Closed Fluid Circulating Systems" by David C. Thornton et al. discloses a system for providing cooling fluid directly to individual components mounted on removable circuit board modules. While this system would be very effective in cooling the individual components, it is complicated and prone to leakage. Furthermore, changes in the design of the circuitry would necessitate a change in the design of the cooling system. U.S. Pat. No. 4,712,158 "Cooling System for Electronic Circuit Components" by Shunichi Kikuchi et al. and in U.S. Pat. No. 3,989,099 "Vapor Cooling Device for Semiconductor Device" by Isamu Hosono et al., both show additional methods of coupling cooling fluid directly to electronic components.
Also of interest in U.S. Pat. No. 4,382,271 "Electrical and Thermal Interconnection System for Electronic Circuit Boards and an Electrical Cabinet Fitted with Such a System" by Claude M. Villemont et al., in that it discloses a method of thermal clamping circuit board modules to more effectively transfer heat therefrom. However, in this final reference there are no provisions for liquid cooling.
Thus, it is a primary object of the subject invention to provide a system for effectively liquid or phase change cooling electronic circuit board modules.
Another primary object of the subject invention is to provide a system for effectively liquid cooling electronic circuit board modules which is light in weight.
It is a further object of the subject invention to provide an effective liquid cooling system for electronic circuit board modules which is both compact and thermally efficient.